In a substrate with built-in electronic component, generally, in an insulating material formed on an electronic component, a via portion for connection with a terminal thereof is formed. For the insulating material, a synthetic resin containing an insulating filler is used. The via portion is formed by laser irradiation or the like over the insulating material.
For example, Japanese Patent Application Laid-open No. 2011-029623 discloses a substrate with built-in component in which a resin layer with built-in component is constituted of a side surface layer formed of a part lower than an upper surface of a chip component and an upper surface layer formed of a part higher than the upper surface of the chip component and having a via conductor formed therein. For the purpose of facilitation of forming a hole of the via conductor by laser irradiation and other purposes, in the substrate with built-in component, a content of an inorganic material such as an insulating filler contained in the upper surface layer is set to be less than a content of the inorganic material such as the insulating filler contained in the side surface layer.